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gordan
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Bugs: SH3 unfit for purpose, especially compared to 2ac

Having had a chance to compare a SH3 with a SH2ac, it may helpful to future visitors of the forum to enumerate the bugs I have found on SH3 that make me seriously wonder if any testing was ever done on the SH3 by anyone, including Arris and Virgin Media. If so (and it is a huge if), it is unbelievable that bugs that a new user runs into within the first 5 minutes of using the hub could have passed any kind of QA.

1) Latency bug (common to all Intel Puma 6 chipset devices, it seems). The first that made it very obvious that something was very badly amiss was the 3.2ms ping time to the SH3's local IP address. On a gigabit LAN I would expect 0.2ms ping times. SH2ac is almost there with 0.5ms ping times, 6.5x faster than SH3.

2) You cannot port forward more than one port range to a machine inside the network. The web interface throws an error instead of adding a 2nd port range.

3) DMZ host must be in the DHCP range. This is quite ridiculous, as it means having to set up a DHCP reservation to make that host's IP address static.

 

SH2ac, OTOH, has been very pleasant to use and I haven't yet hit any bugs on it. The interface is pleasantly responsive, unlike on the SH3, and the number of user accessible configuration options available is an order of magnitude greater than on the SH3.

All this just goes to demonstrate that if you are going to release a product untested, it is indistinguishable from releasing it undeveloped.

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pyrotenax
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Re: Bugs: SH3 unfit for purpose, especially compared to 2ac

Sadly ... and I mean EXTREMELY sadly .. the only way to get the 300Mbps service (Vivid 300) is with the Hub 3.0 Smiley Sad



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gordan
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Re: Bugs: SH3 unfit for purpose, especially compared to 2ac

Are you sure about that? From what I saw in the specs, both are DOCSIS 3.0, so they should both be able to achieve the exact same upstream/downstream channel configuration, and thus the same throughput. DOCSIS 3.0 spec goes up to over a gigabit down and over 200Mbit up.

Have you actually tried using the 300Mbit service using a 2ac, or is this just what VM told you?
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pyrotenax
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Re: Bugs: SH3 unfit for purpose, especially compared to 2ac


gordan wrote:
Are you sure about that? From what I saw in the specs, both are DOCSIS 3.0, so they should both be able to achieve the exact same upstream/downstream channel configuration, and thus the same throughput. DOCSIS 3.0 spec goes up to over a gigabit down and over 200Mbit up.

Have you actually tried using the 300Mbit service using a 2ac, or is this just what VM told you?
Not enough downstream channels on the sh2ac



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gordan
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Re: Bugs: SH3 unfit for purpose, especially compared to 2ac

Interesting, Euro DOCSIS 3.0 spec says 50Mbit/channel, which would imply that SH2ac only supports 4 downstream channels. Yet in the downstream status, the page shows it has 8 channels locked on. So something doesn't quite add up.
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Superuser
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Re: Bugs: SH3 unfit for purpose, especially compared to 2ac

It doesn't quite work like that.

The SH2 is capable of receiving 8 downstream channels, which will give to a theoretical max speed  of 400Mbps accross the 8 channel MAC domain. However, the Domain bandwidth is shared, so the maximum QoS profile would be 200Mbps for load balancing. The rule of thumb is maximum provision = half of the Domain bandwidth.

The Hub 3 can support 24? downstream channels so can support 1200Mbps in theory providing the CMTS can be configured for a 24 Channel MAC Domain(s), so it can run higher speed provisions whilst maintaining load balancing.

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cje85
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Re: Bugs: SH3 unfit for purpose, especially compared to 2ac

gordan wrote:
Interesting, Euro DOCSIS 3.0 spec says 50Mbit/channel, which would imply that SH2ac only supports 4 downstream channels. Yet in the downstream status, the page shows it has 8 channels locked on. So something doesn't quite add up.

 

Technically you could get 300Mb with a SH2, but if you were downloading at that speed it would leave only 100Mb available for other customers connected to the same channels, so congestion problems are likely to develop. For anything over 200Mb more than 8 channels are realistically needed to balance the load. 

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gordan
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Re: Bugs: SH3 unfit for purpose, especially compared to 2ac

Right, but ultimately each channel carries the same amount of data, so why not handle the throughput/congestion issue by distribution of channels between the MAC domains, rather than having each MAC domain claim more channels than it needs and then overbooking the same channels? Is there a technical limitation that prevents distributing the channels so that everybody gets fewer but less congested channels on the ether?
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pyrotenax
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Re: Bugs: SH3 unfit for purpose, especially compared to 2ac


griffin wrote:

It doesn't quite work like that.

The SH2 is capable of receiving 8 downstream channels, which will give to a theoretical max speed  of 400Mbps accross the 8 channel MAC domain. However, the Domain bandwidth is shared, so the maximum QoS profile would be 200Mbps for load balancing. The rule of thumb is maximum provision = half of the Domain bandwidth.

The Hub 3 can support 24? downstream channels so can support 1200Mbps in theory providing the CMTS can be configured for a 24 Channel MAC Domain(s), so it can run higher speed provisions whilst maintaining load balancing.


Yes , I have currently 20 channels downstream and 2 channels upstream in use



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